AB1604 PRE-EXPOSURE PROPHYLAXIS WITH TIXAGEVIMAB/CILGAVIMAB: SINGLE CENTRE EXPERIENCE IN A COHORT OF RHEUMATIC PATIENTS
Authors: F. Cuzzocrea, G. P. Grieco, A. Bartoletti, P. Delvino, G. L. Esposito, D. Lilleri, D. Girardi, M. Cusato, M. Calvi, C. Marena, C. Montecucco, V. Codullo
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Vaccination against SARS-CoV2 had a critical role in the fight against COVID19 pandemic. A weaker humoral response to COVID19 vaccine has been found in rheumatic patients treated with Rituximab (RTX) or Mycophenolate Mofetil (MMF)[1]. Despite the evidence that anti-SARS-CoV-2 mRNA vaccines can elicit a T-cell response [2], some data show that even the cellular immunity could be impaired in rheumatic patients [3] but COVID19 serology is the only parameter that is feasible to measure in daily practice. Tixagevimab+cilgavimab are two human-derived monoclonal antibodies administered parenterally and authorized by regulatory agencies in February 2022 for pre-exposure prophylaxis (PrEP) against COVID19 from different virus variants in fragile patients. <h3>Objectives</h3> To demonstrate safety and effectiveness of tixagevimab+cilgavimab. <h3>Methods</h3> Patients with autoimmune rheumatic diseases undergoing immunosuppressive treatment with RTX or MMF during the vaccination campaign were enrolled between April and June 2022. All patients must have anti-spike antibody levels below the protective threshold (defined by anti-spike IgG titre &lt;250 BAU/ml) after receiving at least 2 vaccine doses. Patients were monitored with a questionnaire every month about COVID19 symptoms (including respiratory and gastrointestinal symptoms, anosmia and ageusia, skin rash and potential contact with COVID19+ subjects) and were checked for anti-spike and anti-nucleocapside antibodies titres every 2 months for a total of a 6 month follow-up. MMF dose was reduced at 1 g/die at the time of vaccine administration. <h3>Results</h3> Fifteen patients were enrolled: 9 participants had a connective tissue disease (CTD; 1 dermatomyositis, 3 anti-syntethase syndrome, 4 systemic sclerosis, 1 systemic lupus erythematosus) and 6 had vasculitis (all granulomatosis with polyangiitis). 12 of them received RTX in the preceding 12 months and 3 were taking MMF. About safety, the therapy was very well tolerated and only 4 patients (26%) reported a non-severe adverse event in the 2 weeks following drug administration (2 myalgia, 1 headache, 1 fatigue), none of them requiring hospitalization nor pharmacologic treatment. Regarding effectiveness, 3/15 patients contracted SARS-Cov2 infection (20%) with mild symptoms and no need for hospitalization nor oxygen therapy. Only 1 of them received an antiviral drug (nirmatrelvir+ritonavir). All infected patients had a CTD diagnosis. No significant correlation was observed between the type of rheumatic disease and the risk of infection or response to tixagevimab+cilgavimab. <h3>Conclusion</h3> None of our patients developed severe adverse events after tixagevimab+cilgavimab administration and, among the 3 SARS-CoV2 infected patients, none required hospitalization nor oxygen therapy. We conclude that in our experience tixagevimab+cilgavimab is a safe and useful complementary immunization strategy to vaccination for COVID19 prophylaxis. These data will be implemented in a larger study, comprehending various immunocompromised patients from several departments. <h3>References</h3> [1] Furer et al., Ann Rheum Dis, 2021 [2] Mangalakumari et al., Nat Rev Immunol, 2020 [3] Picchianti-Diamanti et al., Front Immunol, 2021 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.